package com.ybkj.daijia.page;

import com.ybkj.daijia.page.domain.Sort;
import java.util.List;


/**
 * A slice of data that indicates whether there's a next or previous slice available. Allows to
 * obtain a {@link Pageable} to request a previous or next {@link Slice}.
 *
 * @author Oliver Gierke
 * @since 1.8
 */
public interface Slice<T> extends Iterable<T> {

    /**
     * Returns the number of the current {@link Slice}. Is always non-negative.
     *
     * @return the number of the current {@link Slice}.
     */
    int getNumber();

    /**
     * Returns the size of the {@link Slice}.
     *
     * @return the size of the {@link Slice}.
     */
    int getSize();

    /**
     * Returns the number of elements currently on this {@link Slice}.
     *
     * @return the number of elements currently on this {@link Slice}.
     */
    int getNumberOfElements();

    /**
     * Returns the page content as {@link List}.
     *
     * @return
     */
    List<T> getContent();

    /**
     * Returns whether the {@link Slice} has content at all.
     *
     * @return
     */
    boolean hasContent();

    /**
     * Returns the sorting parameters for the {@link Slice}.
     *
     * @return
     */
    Sort getSort();

    /**
     * Returns whether the current {@link Slice} is the first one.
     *
     * @return
     */
    boolean isFirst();

    /**
     * Returns whether the current {@link Slice} is the last one.
     *
     * @return
     */
    boolean isLast();

    /**
     * Returns if there is a next {@link Slice}.
     *
     * @return if there is a next {@link Slice}.
     */
    boolean hasNext();

    /**
     * Returns if there is a previous {@link Slice}.
     *
     * @return if there is a previous {@link Slice}.
     */
    boolean hasPrevious();

    /**
     * Returns the {@link Pageable} to request the next {@link Slice}. Can be {@literal null} in
     * case the current {@link Slice} is already the last one. Clients should check {@link
     * #hasNext()} before calling this method to make sure they receive a non-{@literal null}
     * value.
     *
     * @return
     */
    Pageable nextPageable();

    /**
     * Returns the {@link Pageable} to request the previous {@link Slice}. Can be {@literal null} in
     * case the current {@link Slice} is already the first one. Clients should check {@link
     * #hasPrevious()} before calling this method make sure receive a non-{@literal null} value.
     *
     * @return
     */
    Pageable previousPageable();
}
